Ultrastructure of the early rostellum of Silurotaenia siluri (Batsch, 1786) (Cestoda: Proteocephalidae)

Abstract

The neodermis of the whole early rostellum of Silurotaenia siluri (Batsch, 1786) bears filamentous microtriches. At the base, there are five to six irregular rows of hooks and spine-like microtriches. The rostellar hooks of S. siluri originate through the enlargement of microtriches. Electron-dense hook substance is deposited along the edges of the microthrix to form the hook blade and basal plate. The blade does not become hollow as in the cyclophyllidean cestodes. The basal plate of the hook, corresponding to the handle and the guard of Cyclophyllidea, is formed by the deposition of hook substance around the base of the microthrix. Within the centre of the base, only a narrow cleft-like core is occupied by distal cytoplasm. The hook bases are more deeply inserted into the distal cytoplasm, as the bases of the spine-like microtriches are localized on the rostellum below the rows of hooks. No hemidesmosomes, fixing the hook base to the basal lamina, are present. Eccrine gland cells and uniciliate and nonciliate sensory receptors of the primitive rostellum are described.

Ultrastructure and histochemistry of the scolex of two Neotropical proteocephalidean species (Cestoda: Onchoproteocephalidea)

“…Two basic types of sensory receptors were observed in proteocephalideans, non‐ciliated and uniciliated, in different regions of the scolex with TEM (Bruňanská et al, 1998, 2000a; Žďárská & Nebesářová, 1999a, 2003). Bruňanská et al (1998, 2000a) studied the receptors in P. longicollis and differentiated among the nonciliated receptors three subtypes according to their structure, and another three subtypes within the ciliated receptors.…”

“…Bruňanská et al (1998, 2000a) studied the receptors in P. longicollis and differentiated among the nonciliated receptors three subtypes according to their structure, and another three subtypes within the ciliated receptors. Additionally, two different types of sensory receptors, uniciliated and non‐ciliate, with a different morphology were reported by Žďárská and Nebesářová (2003) in Silurotaenia siluri , and the presence of receptors in Proteocephalus macrocephalus is also mentioned, although no details of their structure are given (Zďárská & Nebesářová, 1999a).…”

“…In addition, the surface of the scolex and of the strobila is covered by microtriches, which add to the adhesion to the intestinal wall and/or has an absorptive function (Chervy, 2009). The internal ultrastructure of the scolex of the proteocephalideans has been studied in a few Palearctic, Nearctic and Australian species (Andersen, 1979; Bruňanská et al, 1998; Bruňanská et al, 2000a, 2000b; Coggins, 1980; Kuperman & Davydov, 1982; Scholz et al, 1999; Thompson et al, 1980; Threadgold, 1965; Žďárská & Nebesářová, 1999a, 1999b; Žďárská & Nebesářová, 2003; Zďárská, Scholz & Nebesárová, 2004). In those studies, different types of glands, microtriches, and sensory receptors were described.…”

First insights into the activity of major digestive enzymes in the intestine of the European catfish Silurus glanis and protective anti‐enzymatic potential of its gut parasite Silurotaenia siluri

“…In the Upper Volga reservoirs, the European catfish is infected with a specific parasite, the cestode Silurotaenia siluri (Batsch, 1786) (Proteocephalidaae: Gangesiinae) (Zhokhov & Molodozhnikova, 2007). Previous studies have dealt mainly with the morphology and ultrastructure of this helminth (Scholz et al, 1999; Žďárská & Nebesářová, 2003), without addressing such an important issue as its relationship with the definitive host. At the same time, metazoan parasites are known as common natural stressors of freshwater and marine organisms, which can affect host physiology and population structure (Morley, 2019).…”